Rotary screen printing machine

ABSTRACT

A rotary screen printing machine having a plurality of printing sections, wherein when a rotary screen of one printing section is at a position raised from the printing operation position, and the printing operation is conducted by a plurality of printing sections alternately, whereby time required for change of color or design or for washing of screens, squeegees, etc. can be greatly minimized and the machine operation efficiency can be greatly increased.

United States Patent 11 1 Ichinose 1 ROTARY SCREEN PRINTING MACHINE [76]Inventor: Shiro Ichinose, 11-8, 4-chome,

- Shinohara Kita-machi, Nada-ku, v Kobe, Japan [22] Filed: Mar. 9, 1972[21] App]. No.: 233,039

[30] Foreign Application Priority Data Nov. 27, 1973 3,572,240 3/1971BOhm 101/116 3,420,167 l/l969 Van Der Winden 101/116 FOREIGN PATENTS ORAPPLICATIONS 266,650 12/1966 U.S.S.R 101/116 Primary Examiner-Robert E.Pulfrey Assistant ExaminerEugene H. Eickholt AztorneyE. F. Wenderoth etal.

[5 7] ABSTRACT A rotary screen printing machine having a plurality ofprinting sections, wherein when a rotary screen of one printing sectionis at a position raised from the printing operation position, and theprinting operation is conducted by a plurality of printing sectionsalternately, whereby time required for change of color or design or forwashing of screens, Squeegees, etc. can be greatly minimized and themachine operation efficiency can be greatly increased.

8 Claims, 5 Drawing Figures [56] References Cited UNITED STATES PATENTS3,291,044 12/1966 Van Der Winden 101/118 3,585,930 6/197l .Bohm3,565,002 2/1971 Boehm 101/116 PATENTEUHUVZ? ms SHEET 10F 5 (5H1 km wmm2 v I ROTARY SCREEN PRINTING MACHINE This invention relates to a rotaryscreen printing machine having a plurality of printing sections. Moreparticularly, the invention relates to a rotary printing machine havinga plurality of printing sections, wherein when a rotary screen of oneprinting section is in the printing operation position, a rotary screenof another printing section is at a position raised from the printingoperation position, and the printing operation is conducted by aplurality of printing sections alternately.

As compared with, for instance, a flat screen printing machine, a rotaryscreen printing machine can attain a high productivity because of itsspecific mechanism in which high speed printing can be conductedcontinuously, and the rotary screen printing machine is advantageousover the roller printing machine in the printing that the print cost islow. Further, in therotary screen printing machine a color change ordesign change may be accomplished very easily. Accordingly, it may besaid thatthe rotary screen printing machine is a very advantageousprinting machine.

A rotary screen printing machine of the type that has heretofore beenused broadly comprises pulleys provided at both ends of the printingoperation zone, at least one of which is driven, a printing beltsupported and driven by said pulleys, which is adapted for supporting amaterial to be printed and transporting it to the printing operationzone, a squeegee member mounted in the interior of the rotary screen forsqueezing a printing paste or ink into the material to be printedthrough said screen, and a drive mechanism for driving the rotary screenat a speed synchronized with the speed of the printing belt.

However, the known rotary screen printingmachine is still not high inproductivity and machine operation efficiency, because the time requiredfor washing the screens and the squeegee members is considerable at thetime of exchange of color or design and loss of time, therefore, is veryextensive.

Accordingly, itis a primary object of this invention to provide a rotaryscreen printing machine wherein such operations which cause a loss oftime in the conventional machine are accomplished during the printingoperation, whereby the time required for the change of color or designcan be minimized and the machine operation efficiency can be greatlyheight-- ened.

Another object of this invention is to provide a rotary screen printingmachine wherein a plurality of printing sections are provided in theprinting operation zone so that when-a rotary screen of one printingsection is in the printing operation position, a rotary screen ofanother printing section is in a position raised from the printingoperation position, and the printing operation is conducted by aplurality of printing sections alternately.

In accordance with this invention, there is provided a rotary screenprinting machine comprising pulleys provided on both ends of theprinting operation zone, at least one of which is driven, a printingbelt supported and driven by said pulleys, which is adapted forsupporting a material to be printed and transporting it to the printingoperation zone, a squeegee member mounted in the interior of the rotaryscreen for squeezing a printing paste or ink onto the material to beprinted, and a drive mechanism for driving the rotary screen at a speedsynchronized with thespeed of the printing belt, wherein said printingoperation zone comprises a plurality of printing sections independent ofeach other, each of said printing sections comprising at least onerotary screen, a printing frame supporting said rotary screen and a liftmechanism for moving said printing frame vertically, said members beingso arranged that when a rotary screen of of one printing section is inthe printing operation position, a rotary screen of another printingsection is raised from the printing operation position, and thepreparation for printing and the printing operation are conducted by aplurality of sections alternately.

This invention will be explained more fully by reference to theaccompanying drawings, which illustrate an embodiment of this invention.

FIG. 1 is a side view illustrating the drive mechanism of the rotaryscreen printing machine of this invention.

FIG. 2 is a side view illustrating the lift mechanism of the rotaryscreen printing machine illustrated in FIG. 1.

FIG. 3 is an enlarged partial side view illustrating the supportingmechanism for the bearing device of the rotary screen printing machineof this invention.

FIG. 4 is a top plan view illustrating the supporting mechanism for thebearing device shown in FIG. 3.

FIG. 5 is a circuit diagram of the circuit for operating the printingmachine.

In FIGS. 1 and 2, on opposite ends of a frame 1, namely on the ends, andchange zone A, B to zones A and B of the printing operation zone A, B, adrive pulley 2 and an idle pulley 3 are mounted, and a printing endlessbelt 4 is stretched between drive and idle pulleys 2 and 3, andsupported and driven by these pulleys. For driving the drive pulley 2, adrive shaft on which the drive pulley 2 is fixed is provided with asprocket or pulley 6 mounted thereon, and the driving force of a motor Mis transmitted to the drive pulley 2 by means of a chain 9 (or drivebelt 9) extending between a drive sprocket 8 (or pulley 8) of areduction gear 7 mounted on the motor M and said sprocket 6 (or pulley6).

Above the idle pulley 3, a material 10 to be printed, such as a cloth orfabric, is fed on the upper surface of the printing belt 4, andsupported and transported to the printing operation zones A and B by theprinting belt 4. The material 10' which has been printed is separatedfrom the upper surface of the printing belt 4 above the drive pulley 2,following which the material 10' is forwarded to the drying or windingstep. Above the idle pulley 3, a press roller 11 is provided so that ithas a contact with the printing belt 4 travelling on the idle pulley 3,and the material 10 to be printed is fed between the press roller 1 land the printing belt 4 over guide rollers 12 mounted upstream of thepress roller 11. Above the drive pulley 2 there is provided a guideroller 13 to separate from the printing belt 4 the material 10' whichhas been printed and forward it to the subsequent treatment zone.

Above the printing operation zones A and B namely above the printingbelt 4 stretched between the drive and idle pulleys 2 and 3, a pluralityof rotary screens 14 are disposed. In the interior of each rotary screen14 a squeegee member 15 is provided for squeezing a printing ink orpaste onto the material to be printed through said screen. At the timeof the printing operation, the rotary screens '14 contact the material10 to be printed, which is supported on the printing belt 4,

and is driven at a speed synchronized with the travelling speed of theprinting belt 4. Thus, an image of a pattern corresponding to that onthe rotary screen is printed and formed on the material to be printed.Where there is a plurality of rotary screens, their position and phaseare so arranged that a desired pattern or combination of colors can beformed on the material 10 to be printed.

The prominent characteristic feature of this invention is that theprinting operation zone has a plurality of printing sections A and Bindependent of each other and each printing section has at least onerotary screen, a printing frame supporting said rotary screen and a liftmechanism for moving said printing frame vertically. By provision of aplurality of such printing sections, each having an independent liftmechanism, along the single printing belt 4, it is possible when therotary screen of one printing section is in the printing operationposition, namely in the position contacting the material 10 to beprinted which is supported on the printing belt 4, the rotary screen ofthe other printing section is at a position raised from the printingoperation position. As a result, the printing operation can be conductedby a plurality of printing sections A and B alternately, and while oneprinting section is conducting the printing operation, washing of thescreen or squeegee member or changing of the color or design can beeffected in the other printing section.

In the following explanation referring to the drawing, the samereference numbers are used for corresponding members and mechanismscommon to both printing blocks A and B, and when an explanation is givenspecifically for either of the blocks A or B, the letter A" or 8" isprefixed to the reference number.

As is illustrated in FIGS. 1 and 2, two printing sections A and B areprovided along the direction of travel of the printing belt 4. In thisinvention, in order to support rotary screens 14 of sections A and B forvertical movement, a vertically movable printing frame 22 is provided asis illustrated in FIG. 2. In this invention, it is preferred that thebearing device for each rotary screen 14 be mounted on a supportingmember, one end of which is pivoted on a supporting shaft and the otherend of which is attached to the vertically movable printing frame 22,and that a screen gear attached to the rotary screen 14 be engaged witha screen-driving gear through an idle gear on said supporting shaft.

For attaining the above structure, as is illustrated in FIG. 3, thebearing device 16 for each rotary screen 14 is mounted in a supportingmember 21 pivoted at one end 17 on a supporting shaft 18, and the otherend 19 is attached to a vertical member 20 on the printing frame 22. Theshaft 18 is supported rotatably mounted on the frame 1. Thus, thesupporting member 21 can oscillate around the supporting shaft 18 as thecenter, and with oscillation of the supporting member 21, the rotaryscreen 14 can also oscillate around the supporting shaft 18 as thecenter. Each vertical member 20 projects above the printing frame 22,and a mechanism for vertically moving the printing frame 22 is mountedon the frame 1. As can be seen from FIG. 2, one embodiment of such amechanism comprises racks on the printing frame 22 extending in thedownwardly vertical direction, and pinions are rotatably engaged withthe racks 23. One end of an oscillating arm 25 is fixed to each pinion24, and the other end of the oscillating arms 25 are oscillatablymounted on a slide shaft 26.

One end of the slide shaft 26 is attached to an arm 28, one end of whichis oscillatably mounted on a shaft 27. The other end of the arm 28 isconnected with a piston member 30 of a pressure fluid cylinder 29. Whenthe slide shaft 26 is shifted in the right direction by introducing intothe cylinder 29 a pressure fluid such as compressed air or oil, thepinion 24 is rotated in the counter-clockwise direction and the rack 23is shifted upwardly, whereby the printing frame 22, and, in turn, therotary screens 14 are raising up. The lifting and lowering of theprinting frame 22 and the rotatary screens 14 may be accomplished byemploying a known hydraulic machine instead of the lifting and loweringmechanism shown in FIG. 2.

In this invention, it is preferred that, as is illustrated in FIG. 3,the squeegee members 15 be supported by the printing frame 22. If suchmethod of supporting the squeegee members 15 is adopted, the squeegeemembers 15 are shifted a distance corresponding to the lifting distance(h,) of the printing frame 22, while the screens are lifted only adistance expressed by the following equation:

e r X z i wherein h stands for the distance the printing frame 22 israised, 11 indicates the distance the screen 14, d designates thedistance between the supporting shaft 18 and the vertical member 20 ofthe printing frame 22, and d represents the distance from the supportingshaft 18 to the point where each screen 14 comes into contact with thecorresponding squeegee member 15. Accordingly, with the rise of theprinting frame 22, between the inner surface of each screen 14 and endpoint of the squeegee member 15 there is formed a space expressed by thefollowing formula:

Therefore, with the rise of the rotary screens 14, the squeegee members15 move away from the innter surface of the rotary screens 14, with theresult that at the time of stoppage of the printing operation variousoperations can be accomplished smoothly and easily.

The driving of the rotary screens in the printing machine of thisinvention is conducted in the following manner. As is illustrated inFIG. 1, a screen gear 31 is attached to the end portion of each rotaryscreen 14, and the gear 31 is engaged with an idle gear 32 on thesupporting shaft 18. As is illustrated in FIGS. 3 and 4, a shaft 33A ismounted on the vertical member 20, and on both ends of the shaft 33Athere are mounted gears 33 so that the gears 33 are engaged with screengears 31 mounted on both ends of the rotary screen 14. With such aconstruction, by means of the idle gear 32, the drive force transmittedto one end of the screen 14 is conveyed to the other side of the screen14 through the screen gear 31 on one end, the gear 33 on one end, theshaft 33A, the gear 33 on the other end and the screen gear 31 on theother end. By adopting such a construction, an undesired phenomenon oftwisting of the screen can be prevented effectively. Below the idle gear32 on each supporting shaft 18, a screen-driving gear 34 is providedwhich is engaged with said idle gear 32. A helical worm gear 35 ismeshed with the screendriving gear 34, and is engaged with a helicalgear 37 on a screen-driving shaft 36 extending in the longitudinaldirection of the frame 1. By rotation of the screendriving shaft 36, thescreen-driving gear 34 for each rotary screen is driven through theengagement between the helical gear 37 and the helical worm gear 35, andthe drive force of the screen-driving gear 34 is conveyed to the screengear 31 through the idle gear 32, whereby the rotary screens can bedriven and rotated smoothly irrespective of the position of the screens14.

In this invention, it is preferred that the abovementioned drive systembe alternatively connected to a first drive mechanism for driving therotary screens 14 at a speed synchronized with'the speed of the printingbelt 4 and a second drive mechanism independent of said first drivemechanism, whereby at the position raised from the printing operationposition the rotary screens 14 can be driven and rotated independentlyof other known clutch M1 to the first drive mechanism,

and the other end of the screen-driving shaft 36 is connected via amagnetic clutch or other known clutch M2 to the second drive mechanism.Any mechanism capable of driving the rotary screens 14 at a speedsynchronized with the speed of theprinting belt 4 may be utilized as thefirst drive mechanism. For instance, the drive mechanism M for the drivepulley 2 driving the printing belt 4 may be utilized also as the firstdrive mechanism. However, in this invention it is preferred that theidle pulley 3 of the printing belt 4 be used as the first drivemechanism for driving and rotating the rotary screens 14 at a speedsynchronized with the speed of the printing belt 4.

In order to achieve this drive, as is illustrated in FIG. 1, a drivespur gear 39 is fixed on the shaft 38 on which the idle pulley 3 isfixed, an idle gear 40 is mounted to that it is engaged with the drivespur gear 39, and an exchangeable change gear 41 is mounted so that itis engagedwith the idle gear 40. A bevel gear (not shown) is fixed tothe change gear 41. From this bevel gear the drive force is transmittedthrough a bevel gear 42, another bevel gear 43 connected to the bevelgear 42, and still another bevel gear 44 to a drive shaft 45, one end ofwhich is fixed to the bevel gear 44. On the drive shaft 45 are fixed aplurality of spur gears A46 and B46, which are engaged with a spur gearA47 freely movably mounted on the screen-driving shaft A36 of theprinting section A and a spur gear B47 freely movably mounted on thescreen-driving shaft B36 of the printing section B, respectively. Thegears 47 fitted on the screen-driving shafts 36 and the magnetic orother known clutches Ml attached to the shafts 36 are arranged so thatwhen a clutch M1 is actuated, the corresponding shaft 36 is driven androtated by the drive force conveyed to the corresponding gear 47 andwhen a clutch M1 is not actuated, the corresponding spur gear 47 and thescreen-driving shaft 36 can be rotated freely from the other shaft 36and gear 47. Thus, when the clutch M l for one printing section isactuated, with the movement of the printing belt 4 the idle pulley 3 isrotated at a surface speed synchronized with the speed of the printingbelt 4, and the rotation force of the idle pulley 3 is transmitted tothe drive shaft 45 through the gearing mechanism comprising members 39,40, 41, 42, 43 and 44. Then, by the engagement between spur gears 46 and47 for the one printing section the force is conveyed to thescreen-driving shaft 36 for that section, and it is then transmitted tothe rotary screens 14 of that section by means of the gearing mechanismcomprising members 37, 35, 34, 32 and 31. In the manner as describedabove, in this invention, by actuating the clutches AMI and BMI ofprinting sections A and B alternately, either the rotary screens A14 orthe rotary screens B14 can be driven and rotated at a speed synchronizedwith the speed of the printing belt 4. Further, by actuatingsimultaneously both clutches AMI and BMI, all the rotary screens 14 ofprinting sections A and B can be driven and rotated at a speedsynchronized with the speed of the printing belt 4.

In this invention, when the drive system illustrated in FIG. 1 isadopted, even when slippage occurs between the drive pulley 2 and theprinting belt 4, it is possible to drive and rotate the rotary screens14 at a speed completely synchronized with the speed of the printingbelt 4, because the load imposed between the idle pulley 3 and theprinting belt 4 is smaller than the load imposed between the drivepulley 2 and the printing belt 4 and hence, the frequency of slippagebetween the idle pulley 3 and the printing-belt 4 is much lower than thefrequency of slippage between the drive pulley 2 and the printing belt4. Further, the rotation of the rotary screens 14 by the idle pulley 3is not influenced by unevenness of the elongation of the printing belt4. The change of the diameter of a rotary screen 14, i. e., the changeof the design size, may be accomplished easily by exchanging the changegear 41. It is preferred that the idle pulley 40 be mounted oscillatablyaround the shaft 33 yet remain engaged with the drive spur gear 39, sothat a change gear 41 suitable for attaining a speed synchronized withthe speed of the printing belt can be readily attached.

In FIG. 1, to the other end of the screen-driving shaft 36 of eachprinting section is connected a motor 48 equipped with a reduction gearfor driving and rotating the rotary screen independently of the printingbelt 4, through the magnetic or other known clutch M2. When theabove-explained first clutch M1 for one printing section is not actuatedand the second clutch M2 for that section is actuated, thescreen-driving shaft 36 for that section is driven and rotated by themotor 48 equipped with a reduction gear, and the rotary screens 14 forthat section are then driven and rotated by means of the gearingmechanism comprising members 37, 35, 34, 32 and 31.

The printing operation of the printing machine of this invention isconducted in the following manners.

I. Case where the printing operation is conducted by using printingsections A and B alternately:

As is illustrated in FIGS. 1 and 2, the printing frame B22 of theprinting section B is at the lowermost position, namely at the printingoperation position, while the printing frame A22 of the printing sectionA is at a position raised from the operation position, namely at thestoppage position. In this state the printing operation is conducted. InFIG. 1 the first clutch BM1 of the printing section B is acutated, whilethe second clutch BM2 is not actuated. The first clutch AM1 of theprinting section A is not actuated, while the second clutch AM2 iseither actuated or not actuated. The drive pulley 2 is driven androtated by the drive motor M, and with the rotation of the drive pulley2, the endless belt 4 for printing is driven, and a material 10 to beprinted passes over guide rollers 12 and is fed between the pressureroller 11 and the printing belt 4 travelling on the idle pulley 3. Thematerial 111 is supplied to the upper surface of the printing belt 4 andcontinuously forwarded to the printing operation zone.

With rotation of the idle pulley 3 caused by friction with the endlessbelt 4, the drive shaft 45 is driven and rotated. Since the clutch BMIis actuated and the clutch AMI is not actuated, only the screen-drivingshaft B36 of the printing section B is driven and rotated, with theresult that the rotary screens B14 of the printing section B are drivenand rotated at a speed synchronized with the speed of the printing belt4. The rotary screens B14 of the printing section B contact the material10 on the printing belt 4. The squeegee member B has a contact the innersurface of each rotary screen B14, and causes a printing paste or inkfed to the interior of the rotary screen B14 to ooze out through thescreen in the form of a pattern on the material 10 on the printing belt4. Thus, the printing of the material 10 is effectively performed in theprinting section B. The material 10' which has been printed upon isseparated from the printing belt 4 on the discharge end of the printingbelt 4, and is forwarded through a guide roller 13 to the subsequenttreatment zone, for instance, the drying or winding zone. After passageover the drive pulley 2, the endless belt 4 for printing is subjected tosuch treatments as surface washing and drying, and comes to the positionof the idle pulley 3, following which the above operation procedures arerepeated.

Initiation of the printing operation may be effected while maintainingrotary screens 14 at the lower position such as that of the rotaryscreens B14 of the printing block B illustrated in FIGS. 1 and 2.However, in order to prevent wear of the rotary screens 14 at the timeof initiation of the printing operation, it is preferred to initiate theoperation by maintaining rotary screens 14 at the raised position suchas the position of the rotary screens A14 of the printing section A inFIGS. 1 and 2 and to lower the rotary screens coincidentally withinitiation of driving of the printing belt 4.

Coincidentally with the termination of the printing operation in theprinting section B, a fluid is introduced into the fluid cylinder B29,and the lift rack B23 and, in turn, the printing frame B22 are lifted.With the lifting of the frame B22, the rotary screens B14 are rotatedupwardly around the supporting shafts B18 and separate from the material10 to be printed applied, which is applied on the printing belt 4. Alsowith the lifting of the printing frame 22, the top end of the squeegeemembers B15 part from the inner surface of the screens B14. Byintroduction of a fluid into the fluid cylinder 29, disengaging of thefirst clutch BMI and actuation of the second clutch BM2 areautomatically performed coincidentally. As a result, the screendrivingshaft B36 is driven and rotated by the motor B48 equipped with areduction gear, and the rotary screens B14 are driven and rotated,independently of the printing belt 4, by the gearing mechanismcomprising members 37, 35, 34, 32 and 31. Thus, at the time oftermination of the printing operation, rotary screens 14 are lifted fromthe printing operation position, and at this raised position they can bedriven and rotated independently of the printing belt 4, whereby theundesired phenomenon that at the time of stoppage of the printingoperation a printing paste or ink flows out through the screen onto thematerial to be printed or the printing belt can be effectivelyprevented.

Subsequently to the raising of the printing frame B22 of the printingsection B, for conducting the printing operation in the printing sectionA the fluid cylinder A29 of the printing block A is so operated that theprinting frame A22 and, in turn, the rotary screens A14 are lowered tothe printing operation position. Coincidentally, actuation of the firstclutch AMI of the printing section A and disengaging of the secondclutch AM2 are effected, whereby the rotary screen A14 of the printingsection A is driven and rotated at a speed synchronized with thetravelling speed of the printing belt 4. Thus, the printing operation iscontinued by the printing section A.

While the printing operation by the printing section A is being carriedout, a paste-receiving saucer is inserted below each rotary screen B14of the printing section B, and washing of the screen, squeegee anddyestuff pump of the section B and other operations necessary for thenext printing operation are carried out.

The above-mentioned procedures are repeated, and the printing operationcan be continued by printing sections A and B alternately. Accordingly,in the rotary printing machine of this invention, various operationscausing loss of time in the conventional rotary screen printing machinescan be completely accomplished without interruption of the printingoperation. According to the inventors experience, where a design of fivecolors is printed upon a material of 8,000 m length with four colorcombinations, each being 2,000 m length, in the conventional rotaryscreen printing machines at least 30 minutes are required for changingthe color combination after every 2,000 m length of material is printed,and if the printing is conducted at a rate of 40 m/min, it takes 4 hoursand 50 minutes total to accomplish the printing. Thus, the efficiency isabout percent. In contrast, with the rotary screen printing machine ofthis invention, since all the operations required for changing the colorcombination, such as the screenwashing treatment, are completed withoutthe interruption of the printing operation, the time required for suchoperations while the machine is not printing at all is at most 5minutes. Thus, under the same printing conditions, the efficiency can beincreased to about 93 percent in the rotary screen printing machine ofthis invention.

11. Case where the printing operation is conducted by employing printingsections A and B coincidentally:

In the rotary screen printing machine of this invention, the printingoperation may be perfonned also by using the printing sections A and Bcoincidentally. In this case, in the printing sections A and B,actuation of fluid cylinders A29 and B29 and switchover of firstclutches AMI and BMI and second clutches AM2 and BM2 are effected in aparallel manner. Thus, by employing all the rotary screens of printingsections A and B there can be obtained a multi-colored printing, forinstance an eight-colored printing, as is illustrated in FIGS. 1 and 2.

Operation of each printing section is controlled by an electric circuit,for instance, as illustrated in FIG. 5.

In the circuit diagram of FIG. 5, symbol NFB designates a non-fusecircuit breaker, and CS and SS designate change-over switches. SymbolsPB, CR, TR and RF designate a push button switch, a relay, a transformerand a rectifier, respectively. Symbols RA, RB, Ra and Rh each designatea protective resistance. MS and CL designate a magnetic switch and anoverload relay, respectively. SOL A and S01 B designate solenoid valvesA and B for actuating a fluid cylinder. Symbols AMI, BMl, AM2 and BM2each to designate a magnetic clutch, and PM represents a pilot motor.

a. When a push button swich FBI is closed it energizes an excitingcircuit for a realy CR0, and the relay CRO is actuated. At this point,it is necessary that the contact CRI in the circuit of the delay CROshould be in closed, namely CRI should be actuated (the driving speed ofthe belt is maintained at the lowest level). Open contacts CR and CR1 inthe circuit of a switch MSI are closed to actuate the magnetic switchMS], whereby the main motor M is driven. b. When a switch 881 is closedto complete an exciting circuit for a relay CR4, the relay CR4 isactuated and in turn, the magnetic clutch AM]. is also actuated. As aresult, the screens A14 are driven in synchronism with the printingbelt. When a push button switch PB4 is closed to complete in an excitingcircuit for a relay CR8, the relay CR8 is actuated to open contact CR8in a circuit SOL A and cause a fluid cylinder A29 to lower the printingframe A22. in an exciting circuit for a relay CR5, by closing switchSS2, the relay CR5 is actuated, and in turn, a magnetic clutch IBM! isalso actuated. As a result, the screens BM aredriven in synchronism withthe printing belt. In an exciting circuit for a relay CR9, by closing apush button switch PBS, the relay CR9 is actuated, whereby in a circuitSOL B the open contact CR9 is closed and SOL B is actuated to cause afluid cylinder 829 to lower the printing frame B22.

Magneticclutches AMI and BMll, or solenoid valves SOL A and SOL B, maybe actuated coincidentally, or they may be actuated separately.

c. Whena stopping push button BBS provided in the exciting circuit forthe relay CRO is pressed, energization of the relay CRO is. ended, andeach of open contacts CRO connected in parallel to relays CR8 and CR9 isopened. Thus, energization of relays CR8 and CR9 is stopped, and inturn, actuation of solenoid valves SOL A and SOL B is also stopped.(They are returned to the original posi tions by means of springs whenflow of electric current stops.) As a result,-fluid-cylinders A29 andB29 are caused to lift printing frames A22 and B22.

d. When a change-over switch SS2 in an exciting circuit for a relay CR6or a change-over switch SS4 in an exciting circuit for a relay CR7 isclosed, ei-

ther the relay CR6 or CR7 is actuated, whereby a magnetic clutch AM 2 orBM2 is actuated.

Since closed contacts CR4 and CR8 or closed contacts CR5 and CR9 areconnected in parallel to the exciting circuit for the relay CR6 or thatfor the relay CR7, when the magnetic clutch AM! is actuated or when theprinting frame A22 is in the lowered position, it is impossible toactuate the magnetic clutch AM2. Similarly, when the magnetic clutch BM!is actuated or when the printing frame B22 is in the lowered position,the magnetic clutch BM2 cannot be actuated. Magnetic clutches AM2 andBM2 may be actuated either separately or coincidentally.

tact CR7 are connected in parallel to the circuit for the magneticswitch MSA or the circuit for the magnetic switch MSB, only when theprinting frame A22 is lifted and the magnetic clutch AM2 is actuated canthe motor A48 be driven. Similarly, only when the printing frame B22 islifted and the magnetic clutch BM2 is actuated can the motor B48 bedriven.

The motor A48 and the motor Bd8 can be driven either separately orcoincidentally.

By using the above-described circuit, operation of printing sections Aand B can be carried out so as to attain the objects of this invention.Incidentally, adjustment or control of the speed of the printing beltmay be accomplished appropriately by means of both the push buttons FBIand PBS.

I claim:

l. A rotary screen printing machine comprising pulleys at opposite endsof the printing operation zone, at least one pulley being a drivenpulley, a printing belt supported on and driven by said pulleys forsupporting a material to be printed and transporting it to the printingoperation zone, a plurality of rotary screens positioned above said beltin said printing operation zone, a squeegee member in the interior ofeach rotary screen for squeezing a printing paste or ink through therotary screen onto the material to be printed, a first drive mechanismcoupled to said rotary screens for driving the rotary screens at a speedsynchronized with the speed of the printing belt, said machine having insaid printing operation zone a plurality of printing sectionsindependent of each other, each of said printing sections including atleast one of said rotary screens, a printing frame supporting saidrotary screen and a lift mechanism for moving said printing framevertically and operable independently of the lift mechanisms for theother printing sections, whereby the rotary screen of one printingsection can be in the printing operation position, and the rotary screenof other printing section can be at a position raised from the printingoperation position, and the printing operation can be conducted by lessthan all of the printing sections while the parts in the raised printingsection are prepared for printing.

2. A rotary screen printing machine as claimed in claim 1, furthercomprising means associated with each rotary screen comprised of abearing device on which each of the rotary screens is rotatably mounted,a supporting member on which said bearing device is mounted, asupporting shaft on which one end of said supporting member is pivotallymounted, the other end of said supporting memberbeing attached to saidlift mechanism, a screen gear on the rotary screen, an idle gear on saidsupporting shaft engaged with said screen gear, a screen driving gearengaged with said idle gear, a second drive mechanism independent ofsaid first drive mechanism, and means alternatively connecting saidscreen driving gear with said first drive mechanism and said seconddrive mechanism, whereby when the rotary screen of one section is in theprinting operation position, said rotary screen can be driven by thefirst drive mechanism and the rotary screen of other printing block isat a position raised from the printing operation position and can bedriven by the second drive mechanism.

3. A rotary screen printing machine as claimed in claim 2, wherein ineach of the printing sections said lastmentioned means comprises ascreen driving shaft, a gearing mechanism coupled between said screendriving shaft and said screen driving gear, and means at the ends ofsaid screen driving shaft forcoupling said screen driving shaft to saidfirst and second drive means, respectively.

4. A rotary screen printing mechanism as claimed in claim 3 wherein themeans for connecting the screen driving shaft to said first drivemechanism is a first clutch mechanism at one end of said screen drivingshaft, and said means for connecting the screen driving shaft to thesecond drive mechanism is a second clutch mechanism, said first drivemechanism comprising a gearing mechanism coupled to one of said pulleysfor said belt for transmitting the rotation of said pulley, and a driveshaft coupled between said gearing mechanism and said first clutchmechanism for transmitting the rotation of said drive shaft through thefirst clutch mechanism to said screen driving shaft.

5. A rotary screen printing machine as claimed in claim 2 in which saidscreen gear is on one end of said rotary screen, and said machinefurther comprises a further screen gear on the other end of said rotaryscreen, a shaft rotatably mounted on said lifting device, and first spurgear fixed on one end of said shaft and engaged with saidfirst-mentioned screen gear, and a second spur gear on the other end ofsaid shaft engaged with said further screen gear.

6. A rotary screen printing machine as claimed in claim 2, wherein ineach of said printing sections said lift meachanism comprises a verticalmember on which said supporting member is mounted, said verticaly memberbeing coupled to said printing frame, and a fluid pressure actuatedmeans coupled to said vertical member for raising and lowering saidprinting frame and said vertical member.

7. A rotary screen printing machine as claimed in claim 6 in which saidsqueegee member is mounted on said printing frame and positioned withinsaid rotary screen so that when the rotary screen is in contact with thematerial to be printed the blade of said squeegee member is in contactwith the inner surface of the rotary screen, and when the rotary screenis in the raised position, the blade of the squeegee member is spacedfrom the inner surface of the rotary screen.

8. A rotary screen printing machine as claimed in claim 2 in which thereare a plurality of rotary screens in each printing section each havingan associated squeegee member, bearing device, supporting member,

screen gear, idle gear and screen driving gear.

1. A rotary screen printing machine comprising pulleys at opposite endsof the printing operation zone, at least one pulley being a drivenpulley, a printing belt supported on and driven by said pulleys forsupporting a material to be printed and transporting it to the printingoperation zone, a plurality of rotary screens positioned above said beltin said printing operation zone, a squeegee member in the interior ofeach rotary screen for squeezing a printing paste or ink through therotary screen onto the material to be printed, a first drive mechanismcoupled to said rotary screens for driving the rotary screens at a speedsynchronized with the speed of the printing belt, said machine having insaid printing operation zone a plurality of printing sectionsindependent of each other, each of said printing sections including atleast one of said rotary screens, a printing frame supporting saidrotary screen and a lift mechanism for moving said printing framevertically and operable independently of the lift mechanisms for theother printing sections, whereby the rotary screen of one printingsection can be in the printing operation position, and the rotary screenof other printing section can be at a position raised from the printingoperation position, and the printing operation can be conducted by lessthan all of the printing sections while the parts in the raised printingsection are prepared for printing.
 2. A rotary screen printing machineas claimed in claim 1, further comprising means associated with eachrotary screen comprised of a bearing device on which each of the rotaryscreens is rotatably mounted, a supporting member on which said bearingdevice is mounted, a supporting shaft on which one end of saidsupporting member is pivotally mounted, the other end of said supportingmember being attached to said lift mechanism, a screen gear on therotary screen, an idle gear on said supporting shaft engaged with saidscreen gear, a screen driving gear engaged with said idle gear, a seconddrive mechanism independent of said first drive mechanism, and meansalTernatively connecting said screen driving gear with said first drivemechanism and said second drive mechanism, whereby when the rotaryscreen of one section is in the printing operation position, said rotaryscreen can be driven by the first drive mechanism and the rotary screenof other printing block is at a position raised from the printingoperation position and can be driven by the second drive mechanism.
 3. Arotary screen printing machine as claimed in claim 2, wherein in each ofthe printing sections said lastmentioned means comprises a screendriving shaft, a gearing mechanism coupled between said screen drivingshaft and said screen driving gear, and means at the ends of said screendriving shaft for coupling said screen driving shaft to said first andsecond drive means, respectively.
 4. A rotary screen printing mechanismas claimed in claim 3 wherein the means for connecting the screendriving shaft to said first drive mechanism is a first clutch mechanismat one end of said screen driving shaft, and said means for connectingthe screen driving shaft to the second drive mechanism is a secondclutch mechanism, said first drive mechanism comprising a gearingmechanism coupled to one of said pulleys for said belt for transmittingthe rotation of said pulley, and a drive shaft coupled between saidgearing mechanism and said first clutch mechanism for transmitting therotation of said drive shaft through the first clutch mechanism to saidscreen driving shaft.
 5. A rotary screen printing machine as claimed inclaim 2 in which said screen gear is on one end of said rotary screen,and said machine further comprises a further screen gear on the otherend of said rotary screen, a shaft rotatably mounted on said liftingdevice, and first spur gear fixed on one end of said shaft and engagedwith said first-mentioned screen gear, and a second spur gear on theother end of said shaft engaged with said further screen gear.
 6. Arotary screen printing machine as claimed in claim 2, wherein in each ofsaid printing sections said lift meachanism comprises a vertical memberon which said supporting member is mounted, said verticaly member beingcoupled to said printing frame, and a fluid pressure actuated meanscoupled to said vertical member for raising and lowering said printingframe and said vertical member.
 7. A rotary screen printing machine asclaimed in claim 6 in which said squeegee member is mounted on saidprinting frame and positioned within said rotary screen so that when therotary screen is in contact with the material to be printed the blade ofsaid squeegee member is in contact with the inner surface of the rotaryscreen, and when the rotary screen is in the raised position, the bladeof the squeegee member is spaced from the inner surface of the rotaryscreen.
 8. A rotary screen printing machine as claimed in claim 2 inwhich there are a plurality of rotary screens in each printing sectioneach having an associated squeegee member, bearing device, supportingmember, screen gear, idle gear and screen driving gear.